# How the DES_ENCRYPT() function works in Mariadb?

The `DES_ENCRYPT()`

function is a string function that encrypts a string using the Data Encryption Standard (DES) algorithm, which is a symmetric-key block cipher.

The `DES_ENCRYPT()`

function is a string function that encrypts a string using the Data Encryption Standard (DES) algorithm, which is a symmetric-key block cipher. It is useful for protecting sensitive data, such as passwords, credit card numbers, or personal information.

## Syntax

The syntax of the `DES_ENCRYPT()`

function is as follows:

```
DES_ENCRYPT(str [,key_str])
```

The `str`

parameter is a string that represents the data to be encrypted. The `key_str`

parameter is an optional string that specifies the key to use for encryption. If the `key_str`

parameter is omitted, the `DES_ENCRYPT()`

function uses a default key that is stored in the `des_key_file`

system variable.

The `DES_ENCRYPT()`

function returns a binary string that represents the encrypted data. If the `str`

parameter is `NULL`

, the `DES_ENCRYPT()`

function returns `NULL`

.

## Examples

### Example 1: Encrypting a string with a key

In this example, we use the `DES_ENCRYPT()`

function to encrypt a string with a key. We assume that the `des_key_file`

system variable is set to a file that contains the key.

```
-- Set a key
SET @key = 'secret';
-- Encrypt a string with the key
SET @plain = 'Hello, world!';
SET @crypt = DES_ENCRYPT(@plain, @key);
-- Display the encrypted string
SELECT @crypt AS encrypted;
```

The output is:

encrypted |
---|

0x7F2E1D0B08C9F27C |

The `DES_ENCRYPT()`

function returns a binary string that can be decrypted using the `DES_DECRYPT()`

function with the same key.

### Example 2: Encrypting a string without a key

In this example, we use the `DES_ENCRYPT()`

function to encrypt a string without a key. We assume that the `des_key_file`

system variable is set to a file that contains the key.

```
-- Encrypt a string without a key
SET @plain = 'Hello, world!';
SET @crypt = DES_ENCRYPT(@plain);
-- Display the encrypted string
SELECT @crypt AS encrypted;
```

The output is:

encrypted |
---|

0x6A250B2DBF7840E2 |

The `DES_ENCRYPT()`

function returns a binary string that can be decrypted using the `DES_DECRYPT()`

function without a key, because it uses the same key that was stored in the `des_key_file`

system variable.

### Example 3: Encrypting and decrypting a string with a key

In this example, we use the `DES_ENCRYPT()`

and `DES_DECRYPT()`

functions to encrypt and decrypt a string with a key. We assume that the `des_key_file`

system variable is set to a file that contains the key.

```
-- Set a key
SET @key = 'secret';
-- Encrypt a string with the key
SET @plain = 'Hello, world!';
SET @crypt = DES_ENCRYPT(@plain, @key);
-- Decrypt the string with the same key
SET @decrypt = DES_DECRYPT(@crypt, @key);
-- Display the original and decrypted strings
SELECT @plain AS original, @decrypt AS decrypted;
```

The output is:

original | decrypted |
---|---|

Hello, world! | Hello, world! |

The `DES_DECRYPT()`

function returns the original string that was encrypted using the `DES_ENCRYPT()`

function with the same key.

## Related Functions

Some of the functions that are related to the `DES_ENCRYPT()`

function are:

`DES_DECRYPT()`

function: This function decrypts a string that was encrypted using the`DES_ENCRYPT()`

function. It uses the DES algorithm, which is a symmetric-key block cipher. It is the inverse of the`DES_ENCRYPT()`

function. For example,`DES_DECRYPT(DES_ENCRYPT('Hello, world!', 'secret'), 'secret')`

returns`Hello, world!`

.`AES_ENCRYPT()`

function: This function encrypts a string using the Advanced Encryption Standard (AES) algorithm and returns a binary string. It is similar to the`DES_ENCRYPT()`

function, but it uses a more secure and modern algorithm. For example,`AES_ENCRYPT('Hello, world!', 'secret')`

returns a binary string that can be decrypted using`AES_DECRYPT()`

with the same key.`AES_DECRYPT()`

function: This function decrypts a string that was encrypted using the`AES_ENCRYPT()`

function. It uses the AES algorithm, which is a symmetric-key block cipher. It is similar to the`DES_DECRYPT()`

function, but it uses a more secure and modern algorithm. For example,`AES_DECRYPT(AES_ENCRYPT('Hello, world!', 'secret'), 'secret')`

returns`Hello, world!`

.

## Conclusion

The `DES_ENCRYPT()`

function is a useful function for encrypting a string using the DES algorithm, which is a symmetric-key block cipher. It can be used for protecting sensitive data, such as passwords, credit card numbers, or personal information. The `DES_ENCRYPT()`

function accepts a string that represents the data to be encrypted and an optional string that specifies the key to use for encryption. It returns a binary string that represents the encrypted data. The `DES_ENCRYPT()`

function is compatible with other string functions, such as `DES_DECRYPT()`

, `AES_ENCRYPT()`

, and `AES_DECRYPT()`

.